Field of the Invention
Aspects of the present invention generally relate to an ophthalmologic imaging apparatus for capturing an image of an eye fundus of a subject's eye.
Description of the Related Art
In an ophthalmologic imaging apparatus such as a scanning laser ophthalmoscope (SLO) or an eye fundus camera, a panning-tilting mechanism for rotating an apparatus main body in an up-down direction and a right-left direction has been known. The panning-tilting mechanism can change an irradiation angle of measurement light with respect to a subject's eye by making an optional point as a rotation center of the apparatus main body. Generally, when an irradiation angle of the measurement light with respect to the subject's eye is changed by making the pupil center of the subject's eye as a rotation center while maintaining an operation distance between an optical system of the apparatus main body and the subject's eye in an appropriate state, peripheral portions in the eye fundus around the central portion thereof can be observed easily in addition to the central portion of the eye fundus. With respect to the above operation, an apparatus that uses a motor to move an apparatus main body including an optical system along an arc-shape guide has been discussed in Japanese Patent Application Laid-Open No. 2011-245028.
Further, in order to capture a desired position in the eye fundus of the subject's eye with unstable visual fixation, the panning-tilting mechanism may be used to adjust an optical axis of the apparatus main body with an axis of the subject's eye (i.e., a straight line that connects a macula of the eye fundus and a gazing object) to make the measurement light pass through the pupil center. At this time, after an examiner has arranged the apparatus main body at an appropriate operation distance from the subject's eye and completed a focus adjustment thereof, the axis of the eye and the optical axis may be misaligned because of fixation disparity arising in the subject's eye. In such a case, the examiner firstly rotates the apparatus main body by the panning-tilting mechanism to make the axis of the eye and the optical axis substantially conform to each other in order to emit the measurement light substantially vertical to the eye fundus of the subject's eye. Then, the examiner places back the apparatus main body to the appropriate operation distance, and moves the apparatus main body in parallel to allow the measurement light pass through the pupil center of the subject's eye.